This invention relates to an improved low volume spray or sprinkler device for surface irrigation systems and more particularly to such a device that is readily made in two separate pieces, will produce a uniform spray pattern, and will not separate inadvertently due to fluid pressure when installed in a surface conduit.
In the prior art, a spray device, as shown in U.S. Pat. No. 3,815,831, was comprised of two separately molded plastic members including an upper member with a conical deflector and a lower member that was adapted for insertion in a plastic hose or conduit. The upper member or cap was attached to the lower member by means of a peripheral ridge on its lower edge that fit into a groove on the upper end of the lower member above the conduit. This arrangement created a serious problem in that the cap, constantly subjected to fluid pressure from the conduit, often was blown off due to a failure in gripping power by its peripheral ridge. This rendered the spray device inoperative and required replacement of the device. Since a typical surface irrigation system often required many hundreds or thousands of such spray devices, the possibility of such "blow-offs" and their inherent unreliability was intolerable.
A one piece spray device was developed as shown in my U.S. Pat. No. 4,199,105 which alleviated the cap separation problem. However, in order to mold the device as a single unit, it was not possible to provide a conical deflector with relatively long radially extending grooves to control the spray pattern. Instead, the aforesaid device utilized a conical deflector with spaced apart notches along its periphery. These notches provided a spray pattern that was entirely satisfactory for some applications but not as satisfactory as a pattern produced by radial grooves which was required for many other irrigation applications.
It is therefore a general object of the invention to provide an improved low volume spray device for surfact type irrigation systems.
Another object of the invention is to provide a low volume spray device for an irrigation system that can be molded as two plastic members including an upper member having a conical deflector with radial spray controlling grooves and which is connectable to a lower member in such a manner that it cannot be separated therefrom by fluid pressure in the system.
Yet another object of the invention is to provide a low volume spray or sprinkler device that can be readily configured to provide a spray pattern over some predetermined area of less than the full 360.degree. around the device.